Honeywell RTH9585WF: A Smart Thermostat Anyone Can Work
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The Honeywell RTH9585WF is the smart thermostat to buy when you do not want to learn a new gadget. It behaves like a touchscreen version of the programmable thermostat already on your wall, and it adds an app that reaches the house from anywhere.
The catch sits in the wiring. This model needs a C wire, and it does not work with line voltage heating.
What makes this one different from a Nest
Nest built its name on a thermostat that studies your habits and writes the schedule for you.
This one hands the schedule back. You set 7 day programming yourself, the same way you would on a basic programmable model, and the screen is a color touchscreen where the old one had a dial and a menu.
I installed this one myself at the house at the coast, and it has been great.
Honeywell does include a learning feature called Smart Response. It tracks how long your system takes to reach a target temperature, then starts the cycle early so the room hits the number at the hour you asked for.
So what it learns is the equipment timing, and the 7 day schedule stays yours to write.
The Honeywell Home RTH9585WF also displays outdoor temperature and humidity next to the indoor readings, so the wall panel doubles as a weather check.
Those outdoor readings arrive after you finish WiFi setup and register the thermostat.
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The remote start is the reason to own it
The Total Connect Comfort app is the feature that earns its keep, and it earns it hardest on a house nobody is standing in.
Leaving town, I tap the app on my iPhone, and by the time the drive to the coast is over the house is already cool.
A second home, a rental, or any place you show up at on a moving schedule gets the most out of that one button.
Running the system full time to keep an empty house comfortable costs money, and arriving at a hot house and waiting costs comfort. The app takes both off the table.
It also works with Amazon Alexa and Google Home, so a voice command can hold the temperature without anybody walking down the hall.
Honeywell adds alerts through the same app when a filter is due or when extreme temperatures are coming.
Check your wiring before you order
Confirm these three before the box arrives.
- A C wire. The common wire supplies constant power, and the RTH9585WF requires one. Honeywell ships a C wire addendum in the box for exactly that reason.
- A 24 volt system. Honeywell builds this for common 24 volt forced air, hydronic, heat pump, oil, gas, and electric setups. It will not run millivolt systems such as a gas fireplace, or 120 and 240 volt systems such as baseboard electric heat.
- A 2.4GHz WiFi network. Honeywell lists the radio as 802.11b, 802.11g, and 802.11n on the 2.4GHz range, so a 5GHz only network will not hold it.
That last one catches people out in newer homes. If your router hides the 2.4GHz band behind a single combined network name, you may need to split the bands or place a unit closer, and the difference between 2.4GHz and 5GHz on a home network covers how to tell which band you are on.
A thermostat sitting in a hallway is often at the far edge of the signal. Whole home coverage matters more here than raw speed does, a point argued in full in whether you need mesh WiFi or just a better router.
If the hallway is where your signal already drops, fix that before you blame the thermostat, using the sizing numbers in the mesh WiFi system we run across three households.
What to do when there is no C wire
Honeywell runs a free C wire adapter offer on this thermostat, and the notice sits on its own product page.
The adapter wires into the equipment at the furnace or air handler and delivers constant power over the wires already in the wall.
The offer runs on a promo code through Honeywell’s own site, so a thermostat bought elsewhere may not qualify.
Canadian orders are handled by Resideo customer service at retailcustomercare@resideo.com, because the free adapter does not ship to Canada through online checkout.
Running a genuine new C wire is the cleaner fix when the run is short and reachable. Get an HVAC quote before you decide, because the labor is the whole cost.
What the hardware actually supports
The RTH9585WF covers most residential heating and cooling setups.
| Spec | Honeywell RTH9585WF |
|---|---|
| Stages | 3 heat and 2 cool on a heat pump, 2 heat and 2 cool conventional |
| Program type | 7 day programmable |
| Display | Color touchscreen, customizable background |
| Shows | Indoor temperature and humidity, outdoor temperature and humidity, mode, time |
| WiFi | 2.4GHz only, 802.11b, g, and n |
| Certification | ENERGY STAR certified |
| Warranty | 1 year |
| Best for | A home with a C wire and a hallway inside 2.4GHz range |
It measures 4.5 inches wide, 3.5 inches tall, and 0.88 inches deep, so measure the plate it replaces before you patch the wall.
What you give up
A Nest builds the weekly schedule for you, and this Honeywell asks you to build your own. Some buyers came here for exactly that, and for others it is a chore.
The styling is the other limit. The color screen is bright and easy to read, and the housing is still a plain plastic rectangle on the wall.
We have not run a Nest in the same house alongside this one, so treat that comparison as a read of both makers’ published behavior rather than a head to head test.
Two people pushed me toward the Honeywell before I bought it. One installs HVAC for a living and one is a fellow gadget guy, and both landed in the same place.
What it costs
Amazon publishes a list price of $179.99 for this model. Honeywell’s own product page carries no price at all right now and shows the thermostat as sold out.
We started tracking this thermostat in our own price log on August 4, 2026, so the history is only days old. That is not long enough to call a tracked low or a real average, and we will not pretend otherwise.
The buy box came in under that list price on all three days we have logged so far, which is a fact about three days and nothing more.
Check it live before you buy, and today’s reading sits on the Deal Watch price tracker alongside the rest of the products we follow.
Who should buy it
Buy it if you own a second home, a rental, or a house you leave for stretches, and you want the temperature waiting for you when you walk in.
Buy it if the person who has to work the thermostat wants a screen that behaves like the one they already know.
Skip it if your heating runs on line voltage, or if no C wire reaches the wall and running one is more trouble than the upgrade is worth.
Skip it if what you actually want is a thermostat that figures out your week on its own.
Common questions about the Honeywell RTH9585WF
Does the Honeywell RTH9585WF need a C wire?
Yes. It requires a common wire for constant power, and Honeywell includes a C wire addendum in the box.
Does it work with Alexa and Google Home?
Yes. Honeywell lists both, alongside its own Total Connect Comfort app for phone control.
Will it connect to a 5GHz WiFi network?
No. Honeywell specifies 802.11b, g, and n on the 2.4GHz range, so the thermostat needs a 2.4GHz network available.
Does it learn your schedule like a Nest?
No. Smart Response learns how long your system needs to reach a temperature and starts early, and the 7 day schedule stays something you set yourself.
Will it run a gas fireplace or baseboard electric heat?
No. Honeywell builds it for common 24 volt systems, and its guide rules out millivolt systems such as a gas fireplace and 120 or 240 volt systems such as baseboard electric heat.
How long is the warranty?
Honeywell lists a 1 year warranty on this model.